IF you listened to Justice Anthony M. Kennedy of the Supreme Court and his fellow conservatives on the bench this week, you might think the court’s 5-4 decision in the case of Town of Greece v. Galloway was no big deal. So what if a town in upstate New York typically opens its council meetings with prayers that acknowledge “the saving sacrifice of Jesus Christ on the cross”?

If you listened to the people who shepherded the case as it ascended the judicial hierarchy, however, the decision represents one of their biggest victories to date. It “wasn’t just an answer on prayer — it was an answer to prayer!” read a statement by the Family Research Council. The council is one of a host of organizations guided by the religious liberty advocacy group the Alliance Defending Freedom that backed the defendants with legal resources.

To understand why the case’s backers were so cock-a-hoop, you must first know something about the long game being played by the religious right. The goal is to get back to a “soft” establishment of religion in America — that is, a system in which formal guarantees of religious freedom and the official separation of church and state remain in place, but one religion is informally or implicitly acknowledged as the “approved” religion of the majority and a legitimate basis for public policy.

This was more or less the situation in the United States during the first half of the 19th century. In 1811, the New York Supreme Court upheld a conviction for blasphemy (the archetypal union of church and state) on the grounds that the state had an interest in punishing offenses to the religious sensibilities of the Protestant majority. Back then, nativist Protestants imposed their version of the Bible in public schools, while Catholics rioted in protest and placed their children in parochial schools.

Through the 19th and 20th centuries, however, the judicial thinking on church-state issues evolved, and the “soft” establishment became much harder to justify. The United States Supreme Court introduced the “Lemon test,” for example. Named for a 1971 case the court heard, this required that legislation concerning religion should not result in “excessive government entanglement” with religious affairs. The Supreme Court also increasingly took the view that government should abstain from any activity wherein a reasonable observer might perceive it to be endorsing religion.

Today, groups like the A.D.F. — which also represents Conestoga Wood Specialties Corporation in its challenge to the contraception mandate in the Affordable Care Act — are deeply unhappy with the reigning jurisprudence on church-state separation. It would seem that they wish to undermine the Lemon test, which they consider “burdensome,” as a staging post to restoring a soft establishment of Christianity in the United States. This is where Greece v. Galloway comes in.

The first order of business is to remove objections by swiping aside the idea that soft forms of establishment exist at all. Here, the Greece decision delivers, substantially.

“Offense,” Justice Kennedy wrote in his majority opinion, “does not equate to coercion.” Justice Clarence Thomas, in the part of his concurring opinion joined by Justice Antonin Scalia, drew out the key implication: “To the extent coercion is relevant to the Establishment Clause analysis, it is actual legal coercion that counts — not the ‘subtle coercive pressures’ allegedly felt by respondents in this case.” In other words, religious observance counts as “establishment” only if you are compelled to kneel by law.

A second element of the plan for undermining concerns based on the First Amendment’s Establishment Clause is to reinterpret public acts as personal expressions of speech by private individuals. Thus, when the minister appointed by the municipal government of Greece bids “all rise,” the Supreme Court majority tells us, this is not an establishment of religion because the words are not uttered by public officials. And when the town leaders respond with a sign of the cross, that isn’t establishment either, because, just then, public officials are acting as private individuals.

Another prong in the assault on the Establishment Clause is to use neutrality among religious denominations as a wedge for inserting the (presumed) majority religion into state business. In theory, “neutrality” means giving every sect an equal shot at officiating prayer at Greece’s council meetings. In practice, the town government has unquestionably identified itself with what it takes to be the majority religion in the area.

In his concurring opinion, Justice Samuel A. Alito Jr. dismissed concerns about the blatantly sectarian tilt of the town’s proceedings, which were led exclusively by Christian ministers for nearly a decade, by pointing out that Jews make up a mere 3 percent of the local population and alleging that other non-Christian groups are no larger.

A final, crucial part of the strategy is to substitute history — or, more accurately, a particular mythologized version of history — for legal analysis. Here the A.D.F. and its allies have hit pay dirt in the Greece decision.

Justice Kennedy invoked an earlier, highly problematic decision in the case of Marsh v. Chambers to suggest that the usual legal tests were “unnecessary” because the “history supported the conclusion” that the prayers were compatible with the Establishment Clause. It is, however, preposterous to say that something is constitutional simply because it’s been done in the past.

The “history” here sustains a myth that early America had a single religion of “Christianity,” when, in fact, it was bitterly divided into antagonistic sects from the start. And many of America’s founders — James Madison, for example — were firmly opposed to such precedents of church-state entanglement as congressional chaplains.

The assault by the religious right on the Establishment Clause has been unfolding for two decades, in a number of landmark cases. Under cover of pursuing “religious freedom,” it has already succeeded in inserting fundamentalist religion into parts of America’s public education system. With Greece v. Galloway, it has now expanded the reach of this novel and destructive interpretation of the Establishment Clause. It is part of a project to “restore” a version of America that never was, and never can be.